Method of assembling a dynamoelectric machine

ABSTRACT

In a method of assembling a dynamoelectric machine, tabs on a rain shroud are received in releasable engagement in notches in a rabbet surface on an end frame of the dynamoelectric machine so as to locate the rain shroud in an assembly position. The cover is arranged in overlaying relation with the tabs to retain the rain shroud against displacement from its assembly position, and the cover is releasably secured to the end frame thereby to define a compartment between the cover and the end frame for accommodating dynamoelectric machine components.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of copending parent application Ser. No.134,312 filed December 17, 1987 now Pat. No. 4,788,763 which was adivision of then copending grandparent application Ser. No. 864,048filed May 16, 1986 (now U.S. Pat. No. 4,716,326 issued Dec. 29, 1987)which, in turn, was a division of then copending great grandparentapplication Ser. No. 522,620 filed Aug. 12, 1983 (now U.S. Pat. No.4,593,163 issued June 3, 1986), and such parent, grandparent and greatgrandparent applications are respectively incorporated by referenceherein.

BACKGROUND OF THE INVENTION

The present inventions relate generally to electric motors, and, moreparticularly, to motors of the type wherein the energization of motorwindings are controlled by switch mechanisms carried on the motor whichare actuated by axially movable switch actuating members; to motors ofthe type that are to be exposed to moisture such as, for example,moisture conditions such as are encountered in outdoor environments; tomotors having what are known in the art as outboard switch or accessorydevice compartments; and to motors wherein it is desirable to provide amotor carried, externally accessible, switch for determining theoperational mode or condition of such motor.

As will be understood by persons of ordinary skill in the art, singlephase induction motors may be of many different types. Thus, there areresistance start, reactor start, capacitor start, permanent splitcapacitor, and capacitor start-capacitor run motors to name but a few.These different types of motors are characterized by differentspeed-torque characteristics, and of course are capable of beingdesigned to have different theoretical maximum efficiencies. For manyapplications, and especially those where high starting torque isrequired, it is necessary for part of the windings in the motor to bedesigned and arranged to be an auxiliary or starting winding which isenergized during initial excitation of the motor but which isde-energized as the motor comes up to a predetermined speed.

One particular reference work that describes motor characteristics andgives specific application information regarding different motors is theC. G. Veinott book entitled, "Fractional And Subfractional HorsepowerElectric Motors", published by the McGraw-Hill Book Company. For moreinformation on this subject, the reader is directed, for example, to thethird edition of the Veinott book which was copyrighted in 1970 byMcGraw-Hill.

In many applications, it is known to use a centrifugally or otherwiseactuated switch assembly for de-energizing the auxiliary or startingwinding as the motor comes up to speed, and it is desirable to optimizesuch assemblies in terms of material content, assembly cost, andreliability. Some problems with some switch assembly designs that havebeen used heretofore, are believed to have been associated with acondition wherein the switch contacts have been "open" to theirenvironment and subject to damage, or to lodging of foreign material onor about such contacts. Another continuing concern for all types ofmotor circuit controlling switches is the question of accessibility orserviceability of such switches as well as the cost associated withreplacing such switches. It thus also would be desirable to provide anew and improved switch of non-complex design which is reliable inoperation.

In switches of the type here contemplated, the long term maintenance ofdesired dimensional relationships of different switch parts andcomponents is important, in order that desired switch actioncharacteristics result, such as: good contact wiping action; contactself-cleaning action; controlled and limited lost motion relative travelof two or more switch parts; reliable switch action notwithstandingdimensional tolerance accumulations; collinear relationship of contactsand actuator line of travel; weld breaking action; and nearparallelrelationship of two contacts.

In some applications, and especially those applications of motors usedto drive pumps such as jet pumps or swimming pool pumps, circuitcontrolling switches are mounted outboard of one of the motor end framesto facilitate access thereto. In many pump applications, there may beconcern regarding moisture, and it is desirable, e.g., in verticalapplications, to provide rain shrouds to prevent rain from enteringmotor ventilation openings.

SUMMARY OF THE INVENTION

Among the objects of the present invention may be noted the provision ofan improved method of assembling a dynamoelectric machine which at leastin part overcomes the above discussed disadvantageous or undesirablefeatures, as well as others, of the prior art; the provision of suchimproved method in which a plurality of tabs on a rain shroud arereceived in releasable engagement in at least some of a plurality ofnotches provided in a rabbet surface of an end frame for thedynamoelectric machine thereby to locate the rain shroud in an assemblyposition on the end frame; the provision of such improved method inwhich a cover of the dynamoelectric machine is arranged in an assemblyposition on the end frame in overlaying relation with at least the tabsin releasable engagement with the at least some notches thereby toretain the rain shroud against displacement from its assembly position;the provision of such improved method in which the cover is releasablesecured in its assembly position to the end frame thereby to define acompartment between the cover and the end frame for accommodatingdynamoelectric machine components; the provision of such improved methodin which a plurality of threaded fasteners are bottomed out in the endframe to retain the cover against displacement from its assemblyposition; the provisions of such improved method in which a plurality ofresilient seals are respectfully compressed between the cover and thethreaded fasteners thereby to limit the compressive forces exerted bythe threaded fasteners onto the cover when the threaded fasteners arebottomed out in the end frame; and the provision of such improved methodin which the component parts utilized in the practice of such improvedmethod are simplistic in design, easily assembled together andeconomically manufactured. These as well as other objects andadvantageous features of the present invention will be in part apparentand in part pointed out hereinafter.

In general and in one form of the invention, a method is provided forassembling a dynamoelectric machine which includes at least one endframe having a rabbet surface with a plurality of notches therein, arain shroud having a plurality of tabs, and a cover. In the practice ofthis method, the tabs of the rain shroud are received in releasableengagement in at least some of the notches in the rabbet surface of theat least one end frame, and thereby the rain shroud is located in anassembly position on the at least one end frame. The cover is releasablesecured in an assembly position to the at least one end frame, and acompartment means is defined between the cover and the at least one endframe for accommodating dynamoelectric machine components. Whenreleasably secured to the at least one end frame, the cover is arrangedin part in overlaying relation with at least the tabs in theirreleasable engagement with the at least some notches thereby to retainthe rain shroud against displacement from its assembly position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vertically arranged motor ordynamoelectric machine;

FIG. 2 is a perspective view, with parts removed, of a horizontallydisposed motor or dynamoelectric machine;

FIG. 3 is a plan view of the motor shown in FIG. 1, with parts removedtherefrom;

FIG. 4 is a cross-sectional view, with parts removed, looking in thedirection of arrows 4--4 in FIG. 3;

FIG. 5 is a fragmentary view looking in the direction of arrows 5--5 inFIG. 3;

FIG. 6 is a fragmentary looking in the direction of arrows 6--6 in FIG.3;

FIG. 7 is a cross-sectional view, with parts removed and parts brokenaway, looking in the direction of arrows 7--7 in FIG. 3;

FIG. 8 is a view corresponding to FIG. 7 except that it shows acompartment cover in place on the motor end frame;

FIG. 9 is a plan view of a rain shroud shown in assembled relationshipwith the motor in FIG. 1 and illustrating principles which may bepracticed in a method of assembling a dynamoelectric machine in one formof the invention;

FIG. 10 is a cross-sectional view taken in the direction of arrows10--10 in FIG. 9;

FIG. 11 is a cross-sectional view taken in the direction of arrows11--11 in FIG. 9;

FIG. 12 is a cross-sectional view taken in the direction of arrows12--12 in FIG. 9;

FIG. 13 is a fragmentary view in cross-section of the assembledrelationship of the rain shroud of FIG. 9, the compartment cover bestshown in FIG. 1, a motor shell, and a motor end shield whichaccommodates the rain shroud;

FIG. 14 is an enlarged perspective view, with parts broken away, of partof a molded portion of the switch assemblies shown in FIGS. 2, 3, and15;

FIG. 15 is an end view looking into the end of the motor shown in FIG.1;

FIG. 16 is a detailed view of the switch and terminal board shown inFIG. 15;

FIG. 17 is a view taken in the direction of arrows 17--17 in FIG. 16;

FIG. 18 is a view substantially similar to FIG. 16 except that itillustrates a modified mounting position (i.e., height) of the switchand terminal board with respect to mounting posts on the end frame;

FIG. 19 is a view taken in the direction of arrows 19--19 in FIG. 18;

FIG. 20 is an enlarged view of a portion of the switch shown in FIGS. 16and 17;

FIG. 21 is a cross-sectional view taken in the direction of arrows21--21 in FIG. 20;

FIG. 22 is a view of a portion of the structure shown in FIG. 21 butwith the switch arms and contacts in a different position due toactuation of a switch plunger actuator of such switch;

FIG. 23 is an enlarged view of a portion of the switch shown in FIG. 3;

FIG. 24 is a cross-sectional view taken in the direction of arrows24--24 in FIG. 23;

FIG. 25 is a view showing a portion of the mechanism of FIG. 24 with theswitch actuator in an intermediate actuating position;

FIG. 26 is a view of the same structure shown in FIG. 25 but wherein theswitch actuator has travelled further so that two pairs of contacts havebeen closed;

FIG. 27 is a connection diagram for motors utilizing the switchingarrangement shown in FIGS. 15 and 16;

FIG. 28 is a connection diagram for motors using the switchingarrangement shown in FIGS. 3 and 23;

FIG. 29 is a view taken in the direction of arrows 29--29 in FIG. 18 andproviding a typical representation of the multiple mounting surfacetechnique used in switch assemblies illustrated in FIGS. 16 and 23;

FIG. 30 is a view taken in the direction of arrows 30--30 in FIG. 29;

FIG. 31 is an enlarged view illustrating the mounting of a manuallyselectable switch in the motor of FIG. 1;

FIG. 32 is an enlarged perspective view of the switch actuator orplunger that forms part of the switch assemblies shown in FIGS. 15--28;and

FIG. 33 is a cross-sectional view through part of the motor covershowing a fastening scheme employed in the aforementioned assemblingmethod in one form of the invention.

Corresponding reference characters refer to corresponding partsthroughout the several views of the drawings.

The exemplifications set out herein illustrate the preferred embodimentof the present invention in one form thereof, and such exemplificationsare not to be construed as limiting either the scope of such inventionor the scope of the disclosure thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a dynamoelectric motor machine or an electric motor40 arranged in what is commonly referred to as a vertical shaft downposition. As will be understood, the rotatable shaft 41 projecting fromthe motor will be coupled with a pump impeller or any other load that isto be driven by the motor. The motor 40 includes the shell 42 havingupper vent holes 43 therein, an upper end frame which is hidden fromview in FIG. 1 by a rain or drip shroud 44, and a lower end frame 46.The lower end frame includes a number of internally threaded bosses 47by means of which the motor 40 may be assembled with a pump assembly.

Also visible in FIG. 1 is a switch compartment cover or cover means 48which is fastened in an assembly position to the upper end frame bymeans of a pair of axially oriented screw fasteners or fastening means49, an electrical conduit fitting 51 threaded into a tapped hole 52 (seeFIG. 2) of the upper end frame, and a winding energization controlswitch boot 53 (best seen in FIG. 31).

The rain shroud 44 is held in an assembly position or assembledrelationship as part of the complete motor 40 by means of the cover 48,all as will be explained in more detail hereinafter. Thus, separatefastening means are not required for holding the rain shroud on themotor. Moreover, for applications where a rain shroud is neither needednor desired, the shroud simply can be dispensed with and in such anevent, a motor arrangement as shown in FIG. 2 will result where the rainshroud has in fact been dispensed with.

Referring now to FIG. 2, the motor 54 thereshown is substantially thesame as the motor 40 with the exception that it is a single speed ratherthan a two speed motor, it does not include a rain shroud, and a speedor energization selection switch boot 53 is not included. Because ofthis, the cover 56 is slightly different from the cover 48 in that noprovision is made therein for a switch which would protrude therefrom.Such a switch may be provided when the motor is to be operable at twodifferent speeds, or when it is desired to have a line disconnectingswitch at the motor.

A manually operable switch, in the form of a toggle switch, is shown at57 in FIGS. 3 and 31 where it will be seen that the switch is trapped bymeans of a pair of nuts 58 on a switch bracket or bracket means 59 whichin turn is fastened to the end frame 61 by means of a pair of selftapping screws 62. The bracket 59 is dimensioned so that when the cover48 is placed on the motor 40, the recessed surface 63 will fit aboutexposed threads on the switch body. The rubber boot 53, having athreaded nut molded therein, then is threaded onto the switch to providea waterproof arrangement.

With reference now to FIG. 3, the aluminum die cast end frame 61 (as isthe case also with the end frame 64 shown in FIG. 2) is fastened to theopposite end frame by means of clamp bolts 66 which pass through holes67 (see FIG. 4) that are provided in reinforcing bosses 68 which aremolded as unitary parts of the end frame.

Also revealed in FIG. 3 is a two speed switch assembly generally denotedby the reference numeral 69 which is mounted to the end frame by meansof three self tapping screws 71. The switch portion of the switchassembly 69 is illustrated in detail herein in FIGS. 23-26 and adetailed discussion of such assembly will be provided in conjunctionwith a discussion of such figures hereinbelow. The terminal blockportion of the switch assembly 69, on the other hand, is essentially thesame as the terminal block of the single speed switch assembly 72illustrated in detail in FIGS. 16-19, 29, and 30. Because of this, adescription of the terminal block and mounting portion of the switchassembly 69 will be described in detail hereinafter in conjunction withthe terminal block portion of the switch assembly 69.

FIG. 3 further reveals the conduit fitting mounting leg 73, groundingscrew 74, centrifugal switch actuating or operating mechanism 76, astart capacitor 77, and a pair of cast bosses 78, and cast bosses 79,81, and 82. The bosses 78 surround tapped holes 83 which accommodateaxially directed screw fasteners that are used to secure the cover 48 tothe end frame 61. The boss 79, on the other hand, has a hole therein inwhich a self tapping screw 86 may be fastened to hold a capacitor clamp87 in place which of course holds the capacitor 77 in place on the endframe. Underlying the capacitor 77 and holding the capacitor is spacedrelation to the end shield are four cast bosses or capacitor standofflegs 88, two of which may be best seen in FIG. 2.

At this point, it should be noted that, although the end shields 61 and64 are different due to the provision of holes which are used to mount amanually operable switch, the end shields are otherwise identical, andthus like reference numerals have been used to denote like parts andportions of such end frames. Furthermore, in order to simplify thedrawings and avoid confusion, lead wires and jumper leads have not beenshown in any of the views. However, persons skilled in the art willunderstand that lead wires 91 and appropriate jumper wires interconnectthe capacitor 77, terminals on the terminal block portion of the switchassembly, and thermal protectors, such as the protector 92 (see FIG.2)--assuming such a protector is provided. Thus such wires areappropriately interconnected before the cover 48 or cover 46 is placedon the motor. The appropriate connection of such wires and jumpers willbe apparent from FIGS. 27 and 28 herein, and will be describedhereinbelow in conjunction with a discussion of the FIG. 27 and FIG. 28examplary wiring diagrams.

Continuing now with a description of FIG. 3, it will be noted that theboss 81 is provided with a centrally located hole while the boss 82 isprovided with a centrally located pin 80 projecting upwardly therefrom(as viewed in FIG. 3). The use and function of the bosses 81 and 82 inconjunction with mounting the thermal protector 92 of FIG. 2 will bebest appreciated by also considering FIG. 15. Thus, one ear of aprotector 92 is caught on pin 80, while the other ear of the protectoris fastened to boss 81 by means of a self-tapping screw which isthreaded into the hole 85 which is cast in the boss 81. By this means,the protector 92 may be positively mounted quickly and yet with a singlemounting screw.

Considering together FIGS. 3-8 and FIGS. 9-13, the interrelationship ofthe shroud 44, end shield 61, cover 48, and motor shell 42 will bedescribed in detail. With reference first to FIG. 13, it will beunderstood that the end shield 61 includes a rabbet surface 93 alongwhich the cover 48 fits. Also formed in the end shield are a number ofnotches generally denoted by the reference numeral 94 which accommodatetabs 96 (see FIG. 9) formed on the shroud 44. Thus, in order to assemblethe shroud with the motor, the shroud is slipped along the rabbetsurface of the end shield 61 so that the tabs 96 thereon are received inthe notches 94. Subsequent assembly of the plastic cover 48 traps andholds the shroud 44 in place. Thus, notches 94 and tabs 96 define meansfor interfitting in releasable securement with each other to positionrain shroud 44 in assembly relation with end frame 61.

It will be seen from FIG. 9 that four tabs 96 are provided on the shroud44. However, the number of tabs provided is not critical, so long as asufficient number are provided to securely hold the shroud in place andprevent it from being inadvertently separated or torn from a motor towhich it is attached.

Preferably, the shroud is molded from any suitable engineering plasticmaterial. In actual reductions to practice of the invention, Noryl®HS2000 phenylene oxide resin purchased from the General Electric Companywas used for molding the shroud 44.

FIG. 10 represents a "typical" cross-section of the shroud 44. However,in order to provide added strength and rigidity to the shroud, a numberof ribs 97 (see FIG. 12) are molded into the shroud at a number ofspaced apart locations. It also will be noted that two notches areprovided in the shroud, the first one being generally identified at 98to provide clearance for the conduit leg portion of the end shield, anda second notch 99 (see FIG. 11) is provided to accommodate an oil fillertube plug 101 carried by the end frame (see FIGS. 2 and 3).

FIGS. 4 and 5 reveal that the notches 94 are relatively small. Forexample, suitable results have been obtained when the notches wereapproximately 0.375 inches wide (measured across FIG. 5) and about 0.060inches deep (measured across FIG. 4).

An additional notch 102 will also be noted in the rabbet surface 93 (seeFIGS. 3 and 6). The notch 102 is wider than the notches 94 and has beenmade, in actual reductions to practice, to be approximately 0.500 incheswide (across FIG. 6) and approximately 0.035 inches deep. Moreover, thisnotch is located as shown in FIGS. 7 and 8 so that when a cover 48 or 56is positioned on the end frame, a labyrinth drain passage or drain means103 will be defined between the machined surface of the end shield andthe switch compartment cover. This labyrinth drain passage is ofparticular value and use for horizontal shaft applications. In suchapplications, the motor is relatively positioned as shown for example inFIG. 3 with the oil well filler cap 101 at the top of the motor and thedrain notch 102 located at the bottom of the motor. With thisarrangement, any moisture that might condense or otherwise occur insidethe switch compartment will be able to readily drain out of the motorand yet the passageway will be sufficiently small to inhabit entry ofinsects.

The covers 48 and 56 preferably are molded plastic for reasons ofsimplicity, economy, corrosion resistance, general durability, andelectrical isolation. Although substantially any desired engineeringplastic material may be used, preferred embodiments have utilized Noryl®HS2000 thermoplastic material purchased from General Electric Company ismaking the covers 48 and 56.

With reference now to FIGS. 15-19, mounting of the switch assemblies 72and 69 will be explained. It will be noted from FIGS. 7 and 19 that thedie cast aluminum end frames have two mounting posts 104, 106 casttherein as well as a standoff post 105. As will be best appreciated froma review of FIGS. 18, 29, 17, and 19, the terminal board portion of theswitch assembly 72 is provided with a multiple mounting surface designand thus mounting surfaces 107 or 108 may be positioned on top of themounting posts 104, 106, and post 105. In the case of FIG. 17, mountingsurfaces 107 are resting on the top of the posts 104 and standoff. Onthe other hand, in the case of FIG. 19, mounting surfaces 108 areresting on the top of the posts and standoff. With an arrangement suchas that illustrated, it is possible to vary the height of the switchassembly above the top of the end frame as viewed in FIGS. 17 and 19.This is desirable for reasons that are explained hereinbelow. For themoment however, it is sufficient to note that assembly of a switchassembly 69 or 72 with an end frame can be readily accomplished with theassembly at different predetermined heights above the end shield indifferent motors simply by choosing to use mounting holes 110 (in whichcase surfaces 108 will rest upon end shield supporting surfaces) or byusing mounting holes 111 (in which case surfaces 107 will rest upon endshield supporting surfaces). The provision of an elongated slot 109facilitates assembly, and whereas relatively short screws 71 are shownfastening the switch assemblies to the mounting posts 104, 106, arelatively longer screw 100 is threaded into the end frame.

The variable level or height mounting just described may be accomplishedto vary the height of the switch assembly 69 or 72, above the end framewithout having any affect of the interaction between the switchoperating mechanism and the switch assemblies 69, 72. The reason forthis is that the holes 110, 111 are located along an arc of a circlehaving its center at the centers of the switch contacts which areessentially co-incident with the point 113 along which actuating forcesare applied to the switch assembly. Similarly, the slot 109 has itscenter located along a circle that is concentric with the arc defined bythe centers of holes 110 and 111. Of course, the mounting posts orbosses 104, 106, and the holes therein lie along an arc congruent withthe arc that locates the centers of holes 110 and 111.

While two discrete steps have been illustrated such that mountingsurfaces 107, 108 result, it should be understood that three or moresurfaces could be provided to provide either a greater overall range ofmounting height adjustments or "finer" graduated adjustments. Moreover,while discrete steps have been shown and are preferred for providingvariable height mounting surfaces, it should be understood that onecould provide a smooth inclined plane mounting surface (along with slotsrather than discrete holes 110, 111) so that infinitely variablemounting heights could be provided within the range of heights affordedby the two ends of such inclined plane mounting surfaces.

Before leaving FIGS. 16-19, it is further noted that the variousterminals 116 and line terminals L1 and L2 are formed from conventionalelectrical brass material. On the other hand, the molded portions of theswitch assembly and terminal board which will now be described in evenmore detail, are preferably formed from any suitable engineeringplastic. In preferred forms, the switch assemblies illustrated anddescribed herein have been formed from Valox® 420 thermoplastic materialpurchased from the General Electric Company.

The molded portions of the switch assemblies and terminal boards 69, 72are virtually identical. Moreover, all of the parts utilized in theswitch assembly 72 (now to be described in detail) are also present inthe switch assembly 69 except for the fact that one of the switch armsin the switch assembly 69 is elongated as compared to its correspondingarm in the assembly 72.

It will be appreciated from a review of FIGS. 16 and 17, that the switchassembly 72 includes a terminal board portion which includes themounting surfaces previously described, an electrical isolation wall 117separating the terminals L1 and L2, and a reinforcing and protectingwall 118. Also included is a switch arm mounting section which is bestviewed in the upper portion of FIG. 16 and which portion furtherincludes a switch actuator retaining means. The arrangement of thesemeans will be better appreciated by referring to FIGS 20-22 wherein 119generally denotes the switch arm supporting section and the referencenumeral 121 is used to denote a bore defining distal portion whichfunctions as an actuator retainer means and is illustrated in the formof a barrel.

Comparing FIGS. 20 and 21 for a moment, it will be seen that thesupporting section 119 includes a channel defined between a pair ofwalls 122 and a floor 123. Moreover, disposed within such channel is aswitch arm 124 which is fastened to the floor of the channel by means ofa rivet 126. The end of arm 124 is folded back upon itself asillustrated, and the extending double thickness portion thereof forms aspade terminal 116 for connection to a female connector. As will be seenfrom FIG. 21 the arm 124 carries switch contact 127. Overlying theswitch arm 124 and within at least part of the previously mentionedchannel is a second switch arm 128 which carries a contact 129 at onelocation and which is folded upon itself to form a spade terminal 116,and fastened to the switch arm supporting section by a rivet 131. Sincethe connection of the switch arms, rivets, and molded substrates to oneanother by means of a rivet approach is known in the art, furtherdiscussion of such connections is not presented herein.

A perspective detail of the barrel 121 is presented in FIG. 14 and itwill be noted that the barrel includes front and rear slots 132, 133.With the switch arms shown in FIGS. 2-22, it will be appreciated thatboth of these arms project along the slot 132. Disposed within thebarrel 121 is an actuator 134 which is best shown in FIG. 32. Theactuator 134 includes front and rear slots 136, 137 respectively, twoupper flanges 138, and a force transmitting centrally disposed actuatingrib or switch arm driver 139.

As best revealed in FIG. 22, the actuator serves as a plunger having arelatively thick in cross-section (for wear purposes) bottom reactionwall that coacts with a switch mechanism, and side wall portions thatare somewhat less thick in cross-section. As will be appreciated fromFIGS. 20-22, the molded actuator and switch arm support jointlyestablish a maximum open contact gap between the contacts 127, 129.

When assembling the switch assembly 72, an actuator 134 is disposed inthe barrel 121 and the slots 136, 137 (of the actuator) are aligned withthe slots 132, 133 of the barrel 121. Thereafter, the contact and switchblade 124 are positioned in the channel defined by walls 122 and theswitch arm 124 is permanently secured to the floor 123 with the rivet126. When this is accomplished, the tension of the normally flat switcharm 124 holds the actuator 134 in place in the barrel 121.

With reference to FIG. 21, it will be noted that the difference inheight between the floor 123 and the top edge or surface 141 of the rib139 will determine the amount of preload that is placed upon the switcharm 124. This preferably is considered since the switch arm 124 providesthe restoring force to the actuator during switch operation. After theactuator, switch arm 124 and rivet 126 have all been assembled with theswitch supporting section 119, the second or upper switch arm 128 ispositioned along the slots 132, 133 of the barrel 21 and rivet 131 isused to attach the upper switch arm 128 to the switch arm supportingsection 119. An abutment surface 147 locates the free end of arm 128 soas to preload this arm. The amount of such preload is determined as willbe understood, by the mold cavity dimensions which determine therelative locations of surface 147 and the surface 130.

It will be noted that rib guides 142, which act as spacers, are moldedto project from the axially extending interior surface of barrel 121.The outer surface of actuator 134 rides along these ribs and the spacethus provided between the outer surface of actuator 134 and most of theinterior walls of barrel 121 helps assure that dust, dirt, or otherdebris will not cause sticking of the plunger or actuator 134 withinbarrel 121 and thus disturb reliable and consistent switch operation.

When the motor 54 (see FIG. 2) is not running, the conventionalcentrifugal mechanism 76 (see FIG. 15) will be positioned so that theactuating tongue 143 thereof (see FIG. 22) biases the actuator 134upwardly as best shown in FIG. 22. In this condition, the contacts 127and 129 are engaged with one another and power thus would be supplied toan auxiliary or starting winding when it is applied across lineterminals L1 and L2 of the switch assembly 72. It will be noted thatwhen the switch arms 128, 124 are in the deflected positions thereofshown in FIG. 22, there is a force exerted from both of such armsdownwardly against the actuator rib 139. Moreover, it will be noted thatwhen the switch arm 128 is in the position thereof illustrated in FIG.22, a distal portion 146 thereof is spaced from a blade stopping surface147 that is formed as part of the barrel 121. Then, when the motor 54 isenergized, as it comes up to speed, the centrifugal mechanism 76 will,with a snap action, pull the tongue 143 downwardly in the direction ofarrow 148 (see FIG. 22) a distance sufficient that actuator 134 will notcontact tongue 143 even when the flange 138 of the actuator is restingon the upper surface 149 of the barrel 121.

During motor operation, as the tongue 143 (see FIG. 22) snapsdownwardly, the switch arms 124 and 128 immediately snap the actuator134 downwardly. However as the actuator 134 and switch arms 124, 128 aremoving, portion 146 of switch arm 128 impacts the switch arm stoppingsurface 147 and the contact 127 carried by switch arm 124 thereuponseparates from the contact 129 so that they attain their relativepositions thereof as viewed in FIG. 21.

It is desirable that plunger 134 and contact 127 travel as far aspossible during a switch breaking action since the tension or springforce tending to aid breaking is a function of and proportional to theamount of deflection of arm 124. Such deflection, in turn, is a functionof and proportional to the amount of travel of plunger 134. It will beappreciated that tongue 143 undergoes only a finite amount of travel forany given switch operating mechanism. However, with switches designed asshown herein, maximum utilization of the travel of the switch operatingmechanism is attained. Thus, the travel of plunger 134 can be, ifdesired, 100% of the travel of tongue 143. This desirable result occursbecause the movements of contacts 127, 129, plunger 134, and tongue 143are essentially collinear.

With reference now also to the connection diagram illustrated in FIG.27, the auxiliary winding 149 and main windings 151, 152 of motor 42 arenormally not energized when power is not supplied to line terminals L1and L2. However, at that instant in time, switch arms 128 and 124 of theswitch assembly 72 are positioned so that the contacts thereof areclosed. Thus as soon as power is supplied to line terminals L1, L2,power will be supplied to the auxiliary winding 149 through capacitor 77and to both main windings 151, 152. Subsequently, when power is suppliedto line terminals L1, L2, the motor 54 will start, come up to speed, andthe centrifugal switch actuating mechanism will cause the actuator 134to move so that the contacts carried on contact arms 124, 128 willseparate, thus breaking the supply of power to the auxiliary winding149. However, main winding sections 151, 152 will continue to receivepower through the thermal protector 92 and the motor will continue torun. Later, when the motor is de-energized, the centrifugal mechanismwill reset and the tongue 143 thereof will once again close the switchin switch assembly 72.

It should be understood that the capacitor 77 has been shown in thewiring diagram of FIG. 27 and in other views in the drawings herein forpurposes of illustration. However, it should be understood that theswitch assembly 72 and switch assembly 96 may be used with types ofmotors that do not utilize start capacitors such as, for example,resistance split phase motors.

With reference now to FIGS. 23-26, it is noted that the molded portionsof the switch assembly 69 there shown are identical to the moldedportions of the switch assembly 72 shown in FIGS. 20-22 and the relativemovement and operation of such parts are also identical. However, in theswitch assembly 69, the lower or first switch arm 153 is longer than theswitch arm 124 of switch assembly 72. Moreover, the lower switch arm 153carries not only a first contact 127 (which is arranged to engagecontact 129 on switch arm 128) but lower switch arm 153 also carries asecond contact 154. The extended portion of switch arm 153 passes alongthe notches or slots 137 and 133 previously described. Thus, as was thecase also with the switch arms in the switch assembly 72, the parallelalignment of the switch arms 153 and 128 in the switch assembly 69 aremaintained by means of the channel established by the walls 122 as wellas due to the fact that the switch arms pass along and are confined bythe notches 136, 137 of the actuator 134.

The switch assembly 69 further differs from the switch assembly 72 inthat a bifurcated third switch arm structure 156, carrying a contact 157is provided. The two legs of switch arm 156 straddle the other two armsand are attached to the switch arm supporting section 119 by means ofrivets 158 which pass through the holes 159 in the supporting section119. The rivets 158 may also fasten a terminal (not visible in FIG. 23)to the supporting section for connection to a lead wire. Alternatively,such wire may be welded or soldered directly to the end of the arm.

Attention is now directed to FIGS. 20 and 14 and the abutment posts 159that are molded as part of the barrel 121. These abutment posts or earsserve as stops for the switch arm 156 and limit downward travel ofswitch arm 156 when the acutator 134 moves downwardly to the "openswitch" position thereof. Operation of the switch assembly 69, uponmovement of the switch mechanism tongue 143 (see FIG. 26) is the same asdescribed in conjunction with the operation of switch assembly 72. Thus,with reference first to FIG. 26, prior to the time the motor 40 isenergized, both pairs of contacts 127, 129, and 154, 157 are closed.However, when the motor is energized and as it comes up to speed, themechanism tongue 143 snaps downwardly in the direction of arrow 148 asviewed in FIG. 26, with the result that the actuator 134 snaps throughthe position shown in FIG. 25 to the open switch position shown in FIG.24. With the arrangement illustrated in FIGS. 23-26, the switch arm 156contacts the abutment post 159 so that contacts 154 and 157 separatefrom one another with a weld breaking action and thereupon the distal orend portion 146 of the contact arm 128 contacts the blade stoppingsurface 147 of the barrel 121 whereupon further movement of the switcharm 128 is arrested and contacts 127 and 129 separate with a weldbreaking action. This same action also occurs with the structure shownin FIGS. 20-22.

With reference now also to FIG. 28, a connection diagram for the switchassembly 69 in conjunction with motor 40 will be described. In thiscase, the motor 40 is a two speed motor capable of operation either attwo pole speed (3450 rpm) or four pole speed (1725 rpm). In FIG. 28, thetwo pole start winding 161 is connected to the switch arm 156 while thetwo pole main winding 162 is connected to the switch arm 128, whereasone side of the four pole main winding 163 is connected to lowermost,first switch arm 153. The other side of all three windings 161, 162, and163 are connected through a thermal protector, embedded in the windingend turns, to line terminal L2 and thus to one side of the line whenline power is supplied to terminals L1 and L2.

The four pole main winding 163 (which is connected to the switch arm153) is also connected, through a line 164, to the low speed terminal ofthe toggle switch 57. The high speed terminal of the toggle switch 57 onthe other hand is connected to the same blade terminal as the end of thetwo pole main winding 162--i.e., the terminal connected to switch arm128. For high speed operation, the toggle switch will be in the solidline position thereof illustrated in FIG. 28. Thus, when power issupplied to the line, line L1 is connected through the movable contactorof the toggle switch 57 to the contact blade 128. At this instant intime, two pairs of contacts of the switch assembly 69 are closed asshown in FIG. 26. Thus, power will be supplied at that instant to allthree of the windings 161, 162, and 163. However, as the motor comes upto speed both contact pairs open as represented in FIG. 24 with theresult that neither the two pole auxiliary winding nor the four polemain winding are supplied power from the switch arm 128. Thus, the motor40 will have only the two pole main winding 162 thereof energized and itwill operate at high speed.

When the toggle switch 57 is switched to the low speed configurationthereof as represented by dashed lines in FIG. 28, power is supplied toline terminal L1 and thence through line 164 to the four pole mainwinding 163 as well as to the switch arm 153. Since the condition of theswitch assembly 69 at starting is as shown in FIG. 26, power thus willbe supplied from line L1 through the switch arm 153 and contact pairsshown in FIG. 26 through the switch arms 128 and 156 to both the twopole auxiliary winding and the two pole main winding. Thus, for lowspeed operation the motor will start as a two pole high speed motor.However, as the motor comes up to speed, the contact pairs separate andthe switch assembly 69 is in the configuration as illustrated in FIG.24. At this time the three switch arms 128, 153, and 156 areelectrically isolated from one another so that the two pole auxiliarywinding and two pole main winding are no longer energized. Thus, themotor 40 will continue to run as a four pole, low speed motor.

With reference now to FIG. 33, the mode of attaching covers 48 and 56 tothe motors 40 and 54 will be described. It is believed that, heretofore,covers have been made of metallic material and fastened with radiallydirected screws. The arrangements shown herein, however, utilizedirected screws which is more convenient in the field. Moreover,enlarged posts 201 resist the collapsing force resulting from tighteningthe screws 49. As will be seen from FIG. 33, provision is made toprevent the cover from being cracked or otherwise damaged by screw 49.Thus, the tapped hole 202 in the end frame is dimensioned so that screw49 will bottom out therein. The screw 49 and cover 48 are in turndimensioned so that the head of the screw and common steel washer 204thereunder, when considered alone, would not apply any compressive forceon the cover even when the screw is bottomed in hole 202. However,limited, nondamaging compressive force, coupled with a water sealingeffect is provided by a compression washer or resilient seal 206 trappedbetween the steel washer 204 and the cover 48, any suitable compressionwasher or elastomeric material may be used, and in an actual reductionto practice of the invention, 50 durometer rubber having a nominaluncompressed thickness of 0.100 of an inch was used. The dimensions ofthe hole 202, cover 48, screw 49, and washer 204 were such that thewasher 206 was compressed to a thickness of about 0.045 of an inch; withthe screw 49 being dimensioned to a tolerance of plus or minus 0.010 ofan inch.

In this manner, the plastic covers are protected from damage caused byovertightening of screws 48 and a water repelling seal about the screwsis provided by a single means--i.e., the compression washer.

Study of FIG. 33 will also reveal detents or detent means 209 molded inthe internal diameter of hole 202. When the screw 49 is placed in hole202, it can be threaded past detents 209. However, when the cover 48 isremoved in the field, the detents prevent screws 48 from falling out ofthe cover. From the foregoing, it is believed that a novel method ofassembling a dynamoelectric machine has been presented meeting theobjects and advantageous features set out hereinbefore, as well asothers, and it is contemplated that changes in the precise arrangements,shapes, details and connections of the component parts utilized in thepractice of such method, as well as the precise order of the methodsteps of such method, may be made by those having ordinary skill in theart without departing from the spirit of the invention or from the scopethereof, as set out in the claims which follow.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:
 1. A method of assembling a dynamoelectric machine having ashell, at least one end frame secured to the shell, a plurality ofresilient seals, a synthetic material rain shroud, a synthetic materialcover, and a plurality of fasteners, the at least one end frameincluding a generally circumferential rabbet surface, a plurality ofnotches intersecting the rabbet surface, and a plurality of threadedapertures spaced adjacent the rabbet surface, the rain shroud includinga ring portion, a circumferential flange depending in angular relationfrom the ring portion generally radially outwardly thereof, and aplurality of tabs on the ring portion extending generally radiallyinwardly thereof, the fasteners each including a head, and a threadedend generally opposite the head, the cover including an end wall, agenerally annular sidewall depending from the end wall and having a freeend portion, a plurality of bosses integral with the end wall and thesidewall, respectively, and each boss having an abutment end spaced fromthe end wall, and a plurality of openings extending through the bossesintersecting the abutment ends thereof and the end wall, respectively,the method comprising the steps of:placing the ring portion of the rainshroud generally in engagement with the rabbet surface on the at leastone end frame and extending the flange on the rain shroud at least inpart generally circumferentially about a part of the shell so as toextend generally radially outwardly thereof adjacent the at least oneend frame; receiving the tabs on the ring portion in interfittingrelation within at least some of the notches in the at least one endframe, respectively, during the placing step and locating thereby therain shroud in an assembly position on the at least one end frame;disposing the cover in an assembly position on the at least one endframe and defining thereby a compartment means between the cover and theat least one end frame for accommodating dynamoelectric machinecomponents; seating the free end portion on the sidewall of the cover inengagement with the rabbet surface on the at least one end frame andengaging the abutment ends on the bosses of the cover with the at leastone end frame generally about the threaded apertures therein,respectively, during the disposing step; overlaying parts of the freeend portion with the tabs when the tabs are received in the interfittingrelation with the at least some notches, respectively, and retainingthereby the rain shroud against displacement from its assembly position;extending the fasteners in part through the openings in the bosses ofthe cover with the seals being disposed about the fasteners between theheads thereof and exterior parts of the end wall of the cover about theopenings; threadedly engaging the threaded ends of the fasteners withthe threaded apertures, respectively; bottoming the threaded ends in thethreaded apertures during the threadedly engaging step and retainingthereby the cover against displacement from its assembly position; andcompressing the seals in sealing relation between the heads and theexterior parts of the end wall about the openings and limiting therebythe compressive forces applied onto the end wall by the fasteners atleast upon the bottoming of the threaded ends in the threaded apertures,respectively.
 2. A method of assembling a dynamoelectric machineincluding at least one end frame having a rabbet surface with aplurality of notches therein, a rain shroud having a plurality of tabs,and a cover, the method comprising the steps of:releasably receiving thetabs of the rain shroud in releasable engagement in at least some of thenotches in the rabbet surface of the at least one end frame and locatingthereby the rain shroud in an assembly position on the at least one endframe; releasably securing the cover in an assembly position to the atleast one end frame and defining a compartment means between the atleast one end frame and the cover for accommodating dynamoelectricmachine components; and arranging the cover in part in overlayingrelation with at least the tabs in their releasable engagement with theat least some notches during the releasably securing step and retainingthereby the rain shroud against displacement from its assembly position.3. The method as set forth in claim 2 wherein the dynamoelectric machinealso has a plurality of threaded fasteners and wherein the releasablysecuring step includes disposing the cover in its assembly positionbetween parts of the threaded fasteners and the at least one end frameand threadedly engaging the threaded fasteners with the at least one endframe, respectively.
 4. The method as set forth in claim 3 wherein thethreadedly engaging step includes bottoming the threaded fasteners inthe threaded engagement thereof with the at least one end frame,respectively.
 5. The method as set forth in claim 4 wherein thedynamoelectric machine also has a plurality of resilient seals andwherein the releasably securing step further includes compressing theseals between the threaded fastener parts and exterior parts of thecover and limiting thereby the compressive forces exerted by thethreaded fasteners onto the cover at least upon the occurrence of thebottoming step.
 6. The method as set forth in claim 2 wherein the coverincludes an end wall, and a sidewall depending from the end wall andhaving a free end, and wherein the arranging step includes positioningthe free end of the sidewall in engagement with the rabbet surface andin the overlaying relation with tabs to effect the retention of the rainshroud against displacement from its assembly position.